Estimation of Total Body Skeletal Muscle Mass in Chinese Adults: Prediction Model by Dual-Energy X-Ray Absorptiometry

Abstract

BackgroundThere are few reports on total body skeletal muscle mass (SM) in Chinese. The objective of this study is to establish a prediction model of SM for Chinese adults.MethodologyAppendicular lean soft tissue (ALST) was measured by dual energy X-ray absorptiometry (DXA) and SM by magnetic resonance image (MRI) in 66 Chinese adults (52 men and 14 women). Images of MRI were segmented into compartments including intermuscular adipose tissue (IMAT) and IMAT-free SM. Regression was used to fit the prediction model . Age and gender were adjusted in the fitted model. The piece-wise linear function was performed to further explore the effect of age on SM. ‘Leave-One-Out Cross Validation’ was utilized to evaluate the prediction performance. The significance of observed differences between predicted and actual SM was tested by t test and the level of agreement was assessed by the method of Bland and Altman.ResultsMen had greater ALST and IMAT-free SM than women. ALST was the primary predictor and highly correlated with IMAT-free SM (R2 = 0.94, SEE = 1.11 kg, P<0.001). Age was an additional predictor (SM prediction model with age adjusted R 2 = 0.95, SEE = 1.05 kg, P<0.001). There was a piece-wise linear relationship between age and IMAT-free SM: IMAT-free SM = 1.21×ALST−0.98, (Age <45 years) and IMAT-free SM = 1.21×ALST−0.98−0.04× (Age−45), (Age ≥45years). The prediction performance of this age-adjusted model was good due to ‘Leave-One-Out Cross Validation’. No significant difference between measured and predicted IMAT-free SM was detected.ConclusionPrevious SM prediction model developed in multi-ethnic groups underestimated SM by 2.3% and 3.4% for Chinese men and women. A new prediction model by DXA has been established to predict SM in Chinese adults.

Development and validation of anthropometric prediction equations for estimation of lean body mass and appendicular lean soft tissue in Indian men and women

“…This is based on a concept that approximately three-fourths of total body muscle mass exists in the extremities and that appendicular lean tissue is primarily skeletal muscle (17). ALST, therefore, is commonly used as a surrogate of skeletal muscle mass, and DXA estimates of ALST have been validated using the skeletal muscle mass measurements by MRI and CT (3, 12, 28, 32). The guidelines on the diagnosis of sarcopenia also use cut-points based on ALST estimates (7).…”

Development and validation of anthropometric equations to estimate appendicular muscle mass in elderly women

“…An alternative technique is the Dual-energy X-ray Absorptiometry (DXA), which allows measuring the AMM validly when compared with other techniques such as Total Body Nitrogen [25] Nuclear Magnetic Resonance [26] and Computed Tomography [27]. In addition, for being a rapid and practical technique, DXA has been increasingly used in laboratory studies [26,28,29]. However, using DXA in field studies or on a large scale is impractical due to its high cost and logistics required to perform the measurements [30].…”

Estimation of appendicular skeletal muscle: Development and validation of anthropometric prediction equations in Chinese patients with knee osteoarthritis

“…However, almost all authors have suggested that the equation applies only to the population that developed it, and validation in other populations leads to clinically unacceptable bias. 12,[15][16][17]20,28 Currently, we have not found equations specifically developed 18 for healthy Chinese populations (age: 18-69 years), to validate our CV group findings. Although ASM estimated by the equations was related to ASM measured by DXA, the difference was statistically significant (P < 0.001).…”

“…The use of this method in populations with different ethnicities, health conditions or illnesses is reported to have a high R 2 and small SEE. However, almost all authors have suggested that the equation applies only to the population that developed it, and validation in other populations leads to clinically unacceptable bias . Currently, we have not found equations specifically developed for Chinese patients with knee osteoarthritis.…”